Adjustable air cushion for drawing dies



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Patented Apr. 21, 1925.

UNITED: STATES 1,534,435 I PATENT OFFICE.

: MAGNUS E. WIDELL, F MAYWOOD, ILLINOIS, ASSIGNOR TO AMERICAN CAN COM 1 PANY, OF NEW YORK,.N. Y., A CORPORATION OF NEW JERSEY.

ADJ'IISTAIBLE AIR CUSHION FOB DRAWING DIES Application filed May 7,

art of drawing sheet metal articles and has I. for its. object broadly the provision of "means for controlling the action of the a cushion against which the drawing is performed, i. e., the control of the pressure on the metalbeingoperated upon in the drawing operation. a r

I The invention contemplates the prov sion of an air orlother gas cushion for'supportingi the lower drawing die in a die press in such manner and under such control that the pressure of the air cushion may be accurately and positively controlled either at I a con-V stant pressureor with an increase of pres-' sureon such occasionsas maybe necessary or desirable. I 1

Another important object of the invention is'the provision of accurate control for 1 air pressure cushions in drawing apparatus and WhlOll once set n proper ad ustment for the operation upon certain articles may be depended upon to maintain such adjustment and setting without constant attention. of

the press operator. 1

Numerous other and. important objects of the invention will be apparent from the following description, which consideredin con- 1 nection with the accompanying drawings illustrates a preferred embodiment thereof.

The single figure shown on the drawing is D a transverse vertical section through the dles andfluld pressure PIOVlCllIlg means 1n which my present lnventlon 1s embodled for the purposes 'of illustration.

-Upon the drawing is shown a part of a press bolster 1 supporting a drawing die assembly'comprisinga base 2 and carrying a fixed body member 3 and a movable die 4. Themovabledie 4 is adaptedto. co-operate with an upper die 5 when the latter is forced down :to perform the drawing operation. Apertures 6 in the present instance are provided to receive pins 7 supporting v the die 4 and fixed at their lower ends in a pin plate or disk 8. So much of the con- Sanction has 31 st b en d finit 9 1920. Serial No. 379,473.

and well known in the art and further explanation of it is not believed necessary or desirable. A cylinder 9 is positioned be neath the bolster with its upper open end disposed about the pin plate 8 and this pin plate is mounted upon a plunger 11 within the cylinder.

The cylinder is providedat the bottom with a. cylinder head 12 having a large threaded opening 13 at its center. Within this opening is mounted a hollow sleeve 14 forming the stem of a removable bottom 15 located. within the cylinder and adapted to be raised and lowered by rotation of it, the threads on the sleeve and head being'interengaged to this end. A hollow plug or tube 16 extends through the sleeve 14 in threaded engagement therewith as indicated at 17. The tube or plug 16 has a chamber 18 at "its top 1n which is slidahly mounted the stem 190i the plunger 11. This stem 19 has an internal bore 21 extending throughout a part of its length, opening into the chamber 18, at the bottom, and having outlet ports 22 at the top of the bore and well beneath the upper end of the stem. The tube or plug 16 has a'bore 23 in communication with a source. The descent of the dies is accomplished against substantially. a constant pressure until the ports 22 pass into the chamber 'l8, the upper end of the plug acting asa valve to shut off communication between the air pressure source and the space within the cylinder and beneath the piston or plunger. This cutting oif of the communication results in the trapping of air within the cylinder and resulting compression upon further descent of the die, which compression of course increases the pressure of the air cushion. *By reason ofthe threaded connections betweentheparts 12, 14 and .16 this shutting off of communication between the pressure source and thecylinder be accomplished at any point in the action and the: 119

amount of resulting pressure, or in other words the ratio between the pressure at the source and the final pressure, may be altered. and controlled at will. The increasing of the pressure toward the end of the drawing action is of particular value in the making of deep draws.

V'Vhen the pressure in the cylinder is normal, i. e. when the space beneath the plunger is in commimica-tion with the source, the dies are acting against substantially a constant. pressure and it desired the apparatus may be arranged, as will be readily apparent, to permit this condition to prevail throughout the entire drawing action.

In order that the parts 12, ll and 16 may be maintained. in adjusted relation. I provide lock nuts 28 and 29, respectively, upon the parts ll and 16. The part 14 given suitable formation at 81 to permit it to be grasped by a wrench or other turning tool and the end 32 of the plug is similarly shaped. I provide a nut 33 and a washer 34 for holding the fitting 25 in place and against leakage.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and itwill be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbetore described being merely a preferred embodiment thereot.

I claim:

1. In a die press having dies for drawing metal articles, a descending die member and a yieldingly supported companion member, said yielding support for said die member including means forming an air cushion beneath the die and provided with outlet ports which are closed by the movement of the die, and means operated by the die movement for controlling the pressure of said cushion as the drawing action proceeds.

2. In a die press having dies for drawing metal articles, a descending die member and a yieldingly supported companion member, said yielding support for said die member including means forming an air cushion be-' neath the die and provided with outlet ports which are closed by the movement of the die, and means operated by the die movement permitting change of pressure in said cushion.

3. In a die press l'iaving dies for drawing metal articles, a descending die member and a yieldingly suppor ed companion member, said yielding support for said die member including means forming an aircushion beneath the die and provided with outlet ports. which are closed by the movement of the die, and means operated by the die movement for permitting controlled increased pressure in said cushion as the drawing action progresses in predetermined amount.

4. In a die press having dies for drawing metal articles, a descending die member and a yieldingly supported companion member, said yielding support for said die member including means forming an air cushion beneath the die, and means for providing substantially uniform pressure in said cushion throughout a partof the drawing stroke and means operated by the die movement for providing a suddenly increased pressure at a different part of said stroke.

5. In a die press having dies for drawing metal articles, a descending die member and a y-ieldingly supported companion member, said yielding support for said die member including means forming an air cushion be neath the die, and means for maintaining first a constant and then, by the die movement, a suddenly increased pressure in said cushion during the drawing action and for varying the ratio between said constant and increased pressures.

6. In a die press having dies for drawing metal articles, a descending die member and a yieldingly supported companion member, said yielding support for said die member including means forming an air cushion beneath the die, and means for maintaining first a constant and subsequently, and automatically by the die movement, a suddenly increased pressure in said cushion during the drawing action and adjustable to vary the duration of the constant pressure period.

7. In a die press having dies for drawing metal articles, the combination of drawing dies, a cylinder, :1 plunger in the cylinder and rigidly supporting one of said dies, :1 source of air under pressure communicating with the cylinder beneath the plunger, and an air shut-ofi' operable by the plunger at a predetermined point in the drawing action.

8. In a die press having dies for drawing metal articles, the combination of drawing dies, a cylinder, a plunger in the cylinder and rigidly supporting one of said dies, a source of air under pressure communicating with the cylinder beneath the plunger, and an air shut-oft operable by the plunger at a predetermined and adjustable point in the drawing action.

9. In a die press having dies for drawing metal articles, the combination of drawing dies, a cylinder provided with air escape ports which are closed by the die movement, a. plunger in said cylinder and rigidly supporting one of said drawing dies, a source of air under pressure communicating with the cylinder beneath the plunger, and an adjustable bottom in said cylinder for varying the :siZe of the fluid cushion irrespective of the die movement.

10. In a die press having dies for drawing metal articles, the combination of drawing dies, a cylinder. provided with air escape ports which are closed'by the die'movement, a plunger in the cylinder and supporting one of the drawing dies, a source of air under pressure communicating with the cylinder beneath the plunger, said communication being through the plunger stem, and means for cutting ofi' said communication by the die movement.

11. In a die press having dies for drawing metal articles, the combination of drawing dies, a cylinder, a plunger in the cylinder and supporting one of the drawing dies, a source'of air under pressure communicating with the cylinderbeneath the plunger, said communication being through the plunger stem, and an adjustable sleeve embracing said stem and for shutting nflf communication between saidfluid pressure source and the space-beneath the plunger.

12. In a die press for the drawing of metal, the combination of two die members, means whereby said members have relative movement for the drawingoperation, fluid pressure means against which one of the die members is yieldable insaid drawing 0 eration, and cut-ofl' means operated by sai diemovement at a desired stage of the drawing operation for cutting off said fluid pressure means from the; source of such pressure, whereby the further drawing movement proceeds against a highly and automatically increased fluid pressure resistance.

MAGNUS E, WIDELL, 

